Method for preparing silicon carbide/titanium carbide composite ceramics

Abstract

The invention provides a method for preparing silicon carbide / titanium carbide composite ceramics, belonging to the field of inorganic non-metallic materials. The method comprises the following steps: under the protection of inert atmosphere, adding titanocene dichloride and hyperbranched polycarbosilane to a solvent to obtain solution; and depriving the solvent in the solution, ensuring the residues to under cracking reaction in the inert atmosphere and obtaining the silicon carbide / titanium carbide composite ceramics immediately after the reaction is completed. The problem that the mechanical property and high temperature resistance of the composite ceramics are degraded because oxygen is introduced in the process of preparing the silicon carbide / titanium carbide composite ceramics by the existing precursor pyrolysis method is solved by the method provided by the invention, the used process is simple, the cost is low and the prepared silicon carbide / titanium carbide composite ceramics have high yield.

Description

technical field

[0001] The invention belongs to the field of inorganic non-metallic materials, and relates to a preparation method of silicon carbide / titanium carbide composite ceramics. Background technique

[0002] Silicon carbide ceramics have the characteristics of wide band gap, high thermal conductivity, high melting point, high electron mobility, high critical breakdown voltage and good chemical stability. It is an ideal material for devices and circuits, and has broad application prospects in many aspects such as communications, automobiles, aviation, aerospace, and national defense. Precursor conversion method is the main method for preparing silicon carbide ceramics. It was developed by Yajima, Tohoku University, etc. ) was created in 1976. A common precursor to silicon carbide ceramics is polycarbosilane, also known as Yajima polycarbosilane. According to literature (2, Cao F, Li X D, PengP, et al.Structural evolution and ass-ociated properties on conversion fr...

Examples

Embodiment 1

[0019] 1) Under the protection of an inert atmosphere, dissolve titanocene dichloride with dimethylformamide, stir, then add hyperbranched polycarbosilane, the quality of titanocene dichloride, hyperbranched polycarbosilane and dimethylformamide The ratio is 1:1:15;

[0020] 2) The mixture obtained in step 1) is distilled under reduced pressure to remove the solvent;

[0021] 3) The mixture obtained in step 2) was cracked at 1400° C. for 120 minutes under an inert atmosphere to prepare silicon carbide / titanium carbide composite ceramics.

[0022] The average structural formula of hyperbranched polycarbosilane is -[SiH 1.7 (CH 3 ) 0.2 (CH 2 CH=CH 2 ) 0.1 -CH 2 ] n -, determined by thermogravimetric analysis (TGA) (see figure 1 ), the ceramic yield of the hyperbranched polycarbosilane / dichlorotitanocene hybrid precursor at 1400°C was 81.1%, while the ceramic yield of the raw material hyperbranched polycarbosilane at 1400°C was 68.9%; the silicon carbide thus prepared / ...

Embodiment 2

[0024] 1) Under the protection of an inert atmosphere, dissolve titanocene dichloride with tetrahydrofuran, stir, then add hyperbranched polycarbosilane, the mass ratio of titanocene dichloride, hyperbranched polycarbosilane and tetrahydrofuran is 1:3.3:65;

[0025] 2) The mixture obtained in step 1) is distilled under reduced pressure to remove the solvent;

[0026] 3) The mixture obtained in step 2) was cracked at 1300° C. for 10 minutes under an inert atmosphere to prepare silicon carbide / titanium carbide composite ceramics.

[0027] The average structural formula of the raw material hyperbranched polycarbosilane used is-[SiH 1.5 (CH 3 ) 0.5 -CH 2 ] n -, as determined by thermogravimetric analysis (TGA), the ceramic yield of the hyperbranched polycarbosilane / dichlorotitanocene hybrid precursor at 1300°C was 76.4%, while the ceramic yield of the raw material hyperbranched polycarbosilane at 1300°C is 67.5%; the chemical composition of the silicon carbide / titanium carbid...

Embodiment 3

[0029] 1) Under the protection of an inert atmosphere, dissolve titanocene dichloride with chloroform, stir, then add hyperbranched polycarbosilane, the mass ratio of titanocene dichloride, hyperbranched polycarbosilane and chloroform is 1: 2:30.

[0030] 2) The mixture obtained in step 1) is distilled off under reduced pressure in vacuo to remove the solvent.

[0031] 3) The mixture obtained in step 2) was cracked at 1400° C. for 30 minutes under an inert atmosphere to prepare silicon carbide / titanium carbide composite ceramics.

[0032] The average structural formula of the raw material hyperbranched polycarbosilane used is-[SiH 1.5 (CH 3 ) 0.3 (C≡CH) 0.2 -CH 2 ] n -, as determined by thermogravimetric analysis (TGA), the ceramic yield of the hyperbranched polycarbosilane / dichlorotitanocene hybrid precursor at 1400°C was 82.1%, while the ceramic yield of the raw material hyperbranched polycarbosilane at 1400°C is 72.9%; the chemical composition of the silicon carbide / ...

technical field

[0001] The invention belongs to the field of inorganic non-metallic materials, and relates to a preparation method of silicon carbide / titanium carbide composite ceramics. Background technique

[0002] Silicon carbide ceramics have the characteristics of wide band gap, high thermal conductivity, high melting point, high electron mobility, high critical breakdown voltage and good chemical stability. It is an ideal material for devices and circuits, and has broad application prospects in many aspects such as communications, automobiles, aviation, aerospace, and national defense. Precursor conversion method is the main method for preparing silicon carbide ceramics. It was developed by Yajima, Tohoku University, etc. ) was created in 1976. A common precursor to silicon carbide ceramics is polycarbosilane, also known as Yajima polycarbosilane. According to literature (2, Cao F, Li X D, PengP, et al.Structural evolution and ass-ociated properties on conversion fr...

Examples

Embodiment 1

[0019] 1) Under the protection of an inert atmosphere, dissolve titanocene dichloride with dimethylformamide, stir, then add hyperbranched polycarbosilane, the quality of titanocene dichloride, hyperbranched polycarbosilane and dimethylformamide The ratio is 1:1:15;

[0020] 2) The mixture obtained in step 1) is distilled under reduced pressure to remove the solvent;

[0021] 3) The mixture obtained in step 2) was cracked at 1400° C. for 120 minutes under an inert atmosphere to prepare silicon carbide / titanium carbide composite ceramics.

[0022] The average structural formula of hyperbranched polycarbosilane is -[SiH 1.7 (CH 3 ) 0.2 (CH 2 CH=CH 2 ) 0.1 -CH 2 ] n -, determined by thermogravimetric analysis (TGA) (see figure 1 ), the ceramic yield of the hyperbranched polycarbosilane / dichlorotitanocene hybrid precursor at 1400°C was 81.1%, while the ceramic yield of the raw material hyperbranched polycarbosilane at 1400°C was 68.9%; the silicon carbide thus prepared / ...

Embodiment 2

[0024] 1) Under the protection of an inert atmosphere, dissolve titanocene dichloride with tetrahydrofuran, stir, then add hyperbranched polycarbosilane, the mass ratio of titanocene dichloride, hyperbranched polycarbosilane and tetrahydrofuran is 1:3.3:65;

[0025] 2) The mixture obtained in step 1) is distilled under reduced pressure to remove the solvent;

[0026] 3) The mixture obtained in step 2) was cracked at 1300° C. for 10 minutes under an inert atmosphere to prepare silicon carbide / titanium carbide composite ceramics.

[0027] The average structural formula of the raw material hyperbranched polycarbosilane used is-[SiH 1.5 (CH 3 ) 0.5 -CH 2 ] n -, as determined by thermogravimetric analysis (TGA), the ceramic yield of the hyperbranched polycarbosilane / dichlorotitanocene hybrid precursor at 1300°C was 76.4%, while the ceramic yield of the raw material hyperbranched polycarbosilane at 1300°C is 67.5%; the chemical composition of the silicon carbide / titanium carbid...

Embodiment 3

[0029] 1) Under the protection of an inert atmosphere, dissolve titanocene dichloride with chloroform, stir, then add hyperbranched polycarbosilane, the mass ratio of titanocene dichloride, hyperbranched polycarbosilane and chloroform is 1: 2:30.

[0030] 2) The mixture obtained in step 1) is distilled off under reduced pressure in vacuo to remove the solvent.

[0031] 3) The mixture obtained in step 2) was cracked at 1400° C. for 30 minutes under an inert atmosphere to prepare silicon carbide / titanium carbide composite ceramics.

[0032] The average structural formula of the raw material hyperbranched polycarbosilane used is-[SiH 1.5 (CH 3 ) 0.3 (C≡CH) 0.2 -CH 2 ] n -, as determined by thermogravimetric analysis (TGA), the ceramic yield of the hyperbranched polycarbosilane / dichlorotitanocene hybrid precursor at 1400°C was 82.1%, while the ceramic yield of the raw material hyperbranched polycarbosilane at 1400°C is 72.9%; the chemical composition of the silicon carbide / ...

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